I'm thinking if his utterances are so obnoxious and upsetting that everyone that finds them so simply ignore him. If he is factually wrong, dispute him with other facts. The personal attacks merely serve to offer him to answer in kind. IMO it's unseemly. That type of thing gets no one any where. Two wrongs don't make a right.
(BTW, neither side has said anything as bad as some things I heard said in Junior High.)